The purpose of this proposal is to use recent developments in the neuropsychology of antisocial personality disorder (psychopathy) to: (a) clarify the importance of situational and motivational variables in predicting the influence of punishment on the behavior of psychopaths; (b) operationalize a distinctive behavioral style that discriminates between psychopathic and nonpsychopathic offenders; (c) demonstrate a crucial information processing deficit that may account for the psychopath's failure to learn from punishment; and (d) provide behavioral data that will be essential to the evaluation and interpretation of the emerging physiologically-based theories of psychopathy and related syndromes. The experiments, which focus on passive-avoidance as the key deficit in psychopathy, involve the comparison of prison psychopaths and controls on variations of a passive-avoidance task that was developed during the initial period of this grant. Each variation is designed to illustrate a crucial aspect of the person-situation interaction that contributes to the psychopath's passive-avoidance deficit. Based on the neuropsychological model, the psychopath's breakdown in passive-avoidance is conceptualized as a four stage process involving: the formation of a dominant response set; the occurrence of punishment for an inappropriate response; and emotional reaction to the punishment involving facilitation as opposed to inhibition of responding; and a resultant failure to learn the stimulus cues that predict the occurrence of punishment. The anticipated results would provide evidence for a distinctive behavioral style among psychopathic offenders; highlight the situational factors associated with the psychopath's failures of inhibition; and clarify the mechanism through which this behavioral style comes to interfere with learning. In addition to the identification of a distinctive behavioral style among psychopaths that would further efforts to discover the etiology of this disorder, the novel characterization of the psychopathic deficit suggested by this research may provide a context for the development of more effective strategies for the early identification, prevention, and treatment of psychopathy. Finally, the development of the neuropsychological model described in this proposal has implications not only for psychopathy but for a variety of psychopathology and normal behavior involving the interaction of inhibition and arousal.